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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vulnerability analysis of electric power delivery networks

Holmgren, Åke January 2004 (has links)
Disturbances in the services provided by the infrastructuresystems—e.g. electric power supplies and communications—can have serious implications for everyday life,economic prosperity and national security. The disturbances canbe initiated by natural disasters, adverse weather, technicalfailures, human errors, sabotage, terrorism or acts of war. Theaim of this thesis is to study methods for proactivevulnerability analysis of electric power delivery networks(i.e. to analyze their sensitivity to threats and hazards), andto formalize vulnerability as a theoretical concept. The thesis consists of three papers. In the first paper, wediscuss concepts and perspectives for developing a methodologyfor vulnerability studies with the help of the followingthemes: The properties of the infrastructure systems, threatsand hazards, vulnerability and consequence analysis, andmeasures for creating robust and resilient systems. In the second paper we discuss how to assess vulnerabilityof power delivery systems with the help of standard powersystem performance indices. In two case studies, Swedish powerdelivery disturbance data is analyzed with statistical methods.We demonstrate that the disturbance size of large disturbancesfollows a power law distribution, and that the time betweendisturbances is exponentially distributed. In third paper, we model electrical power networks asgraphs, and conduct empirical studies of two power transmissiongrids. We calculate values of topological characteristics ofthe networks and compare their error and attack tolerance, i.e.their performance when vertices are disabled, with twofrequently used model networks. Further, we perform a graphinfluenced vulnerability analysis of a fictitious powernetwork, and evaluate di.erent strategies to decrease thevulnerability of the system.
12

Evaluation of quantitative assessment extensions to a qualitative riskanalysis method / Utvärdering av kvantitativa bedömningsutvidgningar till en kvalitativ riskanalysmetod

Svensson, Louise January 2017 (has links)
The usage of information systems (IS) within organizations has become crucial. Information is one of the most vulnerable resources within an enterprise. Information can be exposed, tampered or made non-accessible, where the integrity, confidentiality or availability becomes affected. The ability to manage risks is therefore a central issue in enterprises today. In order to manage risks, the risks need to be identified and further evaluated. All kind of threats with the possibility to negatively affect the confidentiality, integrity, or availability of the organization need to be reviewed. The process of identifying and estimating risks and possible measures is called risk analysis. There are two main categories of risk analysis, qualitative and quantitative. A quantitative method involves interpreting numbers from data and is based on objective inputs. A qualitative method involves interpreting of subjective inputs such as brainstorming and interviews. A common approach is to apply a qualitative method, however a lot of criticism has been raised against using subjective inputs to assessing risks. Secure State is a consulting company with specialist expertise in the field of information security. They help their customers to build trust in the customers systems and processes, making their customers businesses operate with consideration to information security. One service offered by Secure State is risk analysis, and currently they perform qualitative risk analysis. Given all criticisms against a qualitative approach for assessing risks, this study developed a quantitative risk analysis method for Secure State. According to participants, who attended at a risk analysis where the developed quantitative risk analysis method was used, the quantitative risk analysis method improved the risk assessment. Since risks and their effects are decomposed into smaller components in the proposed quantitative risk analysis method, interpretations of risks and their meaning during assessments less likely differed. Therefore, the common understanding of a risk increases, which makes the quality of the evaluation of risks increase. Furthermore, the usage of statistical data increases in the developed quantitative risk analysis method. Additionally, the quantitative method handles the fact that all data used is imperfect. The data is imperfect since it is used to describe the future, and the future has not happened yet.
13

A Political-security risk analysis of Uganda

Fouche, Philippus Jacobus 20 August 2003 (has links)
The aim of this study is to analyse political-security risk in Uganda. It emanates from the research question: Does Uganda pose a political-security risk to prospective foreign investment or involvement? The need to move beyond a political risk analysis without entering into a country risk analysis, poses the research problem to develop a political-security risk analysis framework and to apply it to Uganda. This problem generates three subsidiary questions: How appropriate (or inappropriate) are existing risk analysis frameworks? Do existing frameworks contain generic elements that can provide a basis for a synthesised framework? To what extent is a country specific framework applicable to other countries? Therefore, three sub-problems are addressed, namely to determine the appropriateness of selected frameworks; to identify generic elements to construct a synthesised framework; and to assess the applicability of this framework for the analysis of political-security risk in other African countries. Following a definition of the concepts risk, country risk, political risk and political-security risk (analysis), selected frameworks for risk analysis were analysed. The generic elements of these frameworks, namely The Economist (EIU), Business Environment Risk Intelligence (BERI), International Country Risk Guide (ICRG) and Political Risk Services (PRS) frameworks, were reduced to three categories and synthesised into a single framework which was applied to Uganda. The categories of risk indicators pertained to security, political and socio-economic risks respectively. These indicators and the allocated risk scores were used to construct a political-security risk index in respect of which the summed scores provided an index figure of risk that was interpreted in accordance with an interpretation scale. In respect of Uganda, its more recent political history was described and the political, security and socio-economic circumstances prevailing in the country analysed. These conditions were assessed and measured against the indicated risk factors and according to the risk index. The summed political-security risk index score for Uganda was 55.5 out of a maximum of 100. In accordance with the interpretation scale, this constitutes an intermediate risk. Based on this Uganda is not, at present, the most suitable destination for foreign investment or involvement. This does not disallow investment or involvement but if indeed the case, it should be done with circumspection. The situation is volatile to the extent that it can rapidly change for the better or the worse, depending on trends concerning the risk categories, or more specifically a turn of events in respect of a particular key risk indicator. Since the synthesised risk analysis framework is able to accommodate key variables pertaining to politics and security in African states, and since it has provided an indication of risk in respect of Uganda, it is suggested for application to other African states. The need for modification, based on the particularities of other countries, is not excluded. It is also proposed that similar exercises be conducted at intervals of six months. This will indicate whether the variables used were, in fact, valid and reliable, and whether additional variables should be included. The repetition of the analysis also indicates risk trends and allows for the monitoring of risks, which will be conducive to risk management. / Dissertation (MSS (Political Sciences))--University of Pretoria, 2003. / Political Sciences / unrestricted
14

Risk Analysis of the applied RFID system : Project Stolpen

Grunzke, Richard January 2007 (has links)
<p>This thesis will be a risk analysis of a RFID-system for a logistical application. The system works as follows: Around Karlstad in Sweden there are three new weighing machines for lorries. The load weight will be measured for the police to control overweight and for logistical reasons such as issuing invoices and optimising the supply chain. The lorries do not have to stop to be weighed. They have to drive slowly over the weighing machine, so the loss of time is minimal. The lorries will be identified via RFID-tags. So every time a lorry will be driven over the weighing machine, the identification number and the measured weight will be logged and send to a database. In the future it is planed to store the weight on the tag itself. The task is now to analyse the RFID-communication and the transmission to the database. The thesis will contain several parts. First RFID in general and how RFID will be used in the application-scenario will be described. Next sections will be about the security and privacy requirements and the risks in detail. Then possible solutions are outlined and concrete suggestions are presented. Finally a conclusion will be drawn, which will show that the application has a low level of security.</p>
15

The impact of portfolio strategy on the property 'style' performance of UK property companies

Mohd Ali, Hishamuddin January 2001 (has links)
No description available.
16

The use of qualitative risk analysis methods to facilitate decision making in the management of health and welfare in wildlife

Hartley, Matthew January 2018 (has links)
This thesis is composed of a series of papers, all of which have been published in peer reviewed publications. The papers use the recognised process of qualitative risk assessment in a range of scenarios in the field of wildlife health and welfare in both in situ and ex situ environments. Chapter 1 discusses the challenges faced regarding availability of empirical data in field of wildlife and zoological health and welfare and justifies the exploration of techniques to assist with decision making. The development of risk analysis and its integration with risk management and risk communication to become risk assessment is described before being put into the specific context of wildlife and zoological disease. Chapters 2 and 3 consider two scenarios where disease risk assessment is well established as a tool, importation across national borders and in conservation interventions. Chapter 2 develops the standard import risk assessment approach to include multiple species and multiple diseases. Chapter 3 reviews developments made over the last 25 years and proposes best practice approaches to implement. Chapter 4 describes how the risk assessments formulated as described in Chapter 3 are used for licensing purposes emphasising the importance of risk management and communication. This theme is continued in Chapter 6 where the integration of risk assessment and evidence based decision making is considered in the broad context of a strategic approach to wildlife health bringing together the outcomes and processes described in Chapters 2, 3, 4 and 5. The papers in Chapters 2,5 and 8 are focused on how risk analysis aids in development of disease control approaches and policy. The evidence base is composed primarily of peer-reviewed literature supported by expert review of the finalised assessment. Chapter 7 uses risk assessment in an applied scenario, taking the recognised process and modifying it to structure an active disease investigation demonstrating the versatility of the technique. Chapter 9 takes this a step further by again adapting the methodology which, has historically been used primarily for infectious diseases, to consider reproduction and assess risks to welfare rather than purely health. The paper in Chapter 9 builds on the methodology by combining existing peer-reviewed literature with data collected specifically for the purpose of feeding into the assessment and utilising a stakeholder and expert opinion elicitation workshop to obtain data too. These process are proposed and described in Chapter 3. The final chapter critically reviews risk assessment, highlighting three key areas of potential weakness and proposing approaches to address these criticisms. The value of the approach in wildlife and zoological health and welfare as demonstrated by this series of papers is described.
17

Risk analysis associated with flank failure from Putauaki, Bay of Plenty, New Zealand

Hewitt, Dolan January 2007 (has links)
Volcanoes are dynamic evolving structures, with life cycles that are punctuated by episodes of flank instability. Putauaki (Mount Edgecumbe) is a stratovolcano located onshore in the Bay of Plenty, New Zealand. The aim of this study was to assess the stability of Putauaki and analyse the risk associated with volcanic collapse. To achieve this objective, a multidisciplinary approach was used, incorporating geomorphological and geological mapping, rock mass classification, laboratory testing to identify geotechnical properties of materials representative of the volcano, stability modelling, and analysis of landslide run-out zones. Putauaki comprises two predominant features including the larger and younger Main Cone (the summit lying 820 m a.s.l., slope angles up to 36 ), and smaller and older Main Dome (the summit lying 420 m a.s.l., slope angle of 24 ). Both features show little evidence of erosion or surface water. Rock mass description defined six lithotechnical units including indurated andesite, indurated dacite, scoriaceous andesite, altered andesite (all categorised as hard rocks), and block and ash flow and Matahina Ignimbrite (both categorised as soft rocks). The uniaxial compressive strength (UCS) of indurated andesite and indurated dacite was 60 4 MPa and 44.7 0.9 MPa respectively, correlating with moderately strong rock. Discontinuities of the indurated units were widely spaced, showed medium persistence and wide aperture, and were slightly weathered. Infill comprised predominantly loosely packed, very strong, coarse gravel. UCS of scoriaceous andesite and altered andesite was 25 5 MPa and 15 1 MPa respectively, allowing categorisation as very weak rock. Discontinuities of scoriaceous andesite were widely spaced, showed high persistence and wide aperture, and were moderately weathered. Discontinuities of the altered andesite were moderately spaced, showed low persistence and wide aperture, and were highly weathered. Infill of scoriaceous and altered andesite was loosely packed, moist, weak to very weak medium gravel. The block and ash flow was a poorly sorted, loosely packed, sandy, gravely and cobble rich matrix supported deposit. The Matahina Ignimbrite was a very weak, discontinuity-poor deposit. Shear box testing indicated cohesion and friction angle of 0 MPa and 42.1 (block and ash flow) and 1.4 x 10-3 MPa and 41.7 (Matahina Ignimbrite) respectively. These values are similar to published values. Correlation of each lithotechnical unit to its respective rock mass description site allowed approximate boundaries of each unit to be mapped. Each unit's mass strength was combined with measured bulk densities and incorporated into two dimensional slope profiles using the stability modelling package GalenaTM. Ten slope profiles of Putauaki were constructed. Failure surfaces for each slope profile were defined using the Bishop simplified multiple analysis method. Four slope profiles showed the potential for small scale failure (less than 0.1 km2 of material). The remaining six slope profiles showed the potential for large scale failure (greater than 0.1 km2 of material). Stability of these six slope profiles was investigated further in relation to earthquake force, watertable elevation, and a disturbance factor of the rock mass (D). Conditions of failure graphs for profile 6a showed that at low D (less than 0.4), earthquake forces and watertable elevation must be unrealistically high for the region (greater than 0.33 g; greater than 15% watertable elevation) in order produce a factor of safety less than 1. The remaining five slope profiles showed potential to be unstable under realistic earthquake forces and watertable elevations. Two of these profiles were unable to achieve stability at D greater than 0.8 (profile 4) and D greater than 0.9 (profile 5). A D value of 0.6 (intermediate between 0.4 and 0.8) is argued to most realistically represent Putauaki. The fact that Putauaki has not undergone large scale failure to date supports the conclusion that the constructed models overestimate the influence of those factors which promote slope instability. Maximum and minimum landslide run-out zones were constructed for the slope profiles exhibiting the potential for large scale failure. Definition of the position and extent of maximum and minimum run-out zones assumed H/L (fall height to run-out length) ratios of 0.09 and 0.18 respectively, as well as the 'credible flow path' concept. Identified impacts of landslides sourced from Putauaki include inundation of Kawerau Township, Tarawera River, forestry operations, road networks, and power supplies. Based on these impacts, the risk posed by landslides from each slope profile was categorised as ranging from relatively low to relatively high. Landslides sourced from the south-west flanks pose a relatively low risk due to their prerequisite of unrealistically high watertable elevations and earthquake forces. Landslides sourced from the north-west flanks pose a relatively high risk as minimum run-out will inundate north-east parts of Kawerau Township. Landslides sourced from the eastern flanks pose a moderate risk due to their run-out zones avoiding Kawerau Township.
18

Quantitative transportation risk analysis based on available data/databases: decision support tools for hazardous materials transportation

Qiao, Yuanhua 17 September 2007 (has links)
Historical evidence has shown that incidents due to hazardous materials (HazMat) releases during transportation can lead to severe consequences. The public and some agencies such as the Department of Transportation (DOT) show an increasing concern with the hazard associated with HazMat transportation. Many hazards may be identified and controlled or eliminated through use of risk analysis. Transportation Risk Analysis (TRA) is a powerful tool in HazMat transportation decision support system. It is helpful in choosing among alternate routes by providing information on risks associated with each route, and in selecting appropriate risk reduction alternatives by demonstrating the effectiveness of various alternatives. Some methodologies have been developed to assess the transportation risk; however, most of those proposed methodologies are hard to employ directly by decision or policy makers. One major barrier is the lack of the match between available data/database analysis and the numerical methodologies for TRA. In this work methodologies to assess the transportation risk are developed based on the availability of data or databases. The match between the availability of data/databases and numerical TRA methodologies is pursued. Each risk component, including frequency, release scenario, and consequence, is assessed based on the available data/databases. The risk is measured by numerical algorithms step by step in the transportation network. Based on the TRA results, decisions on HazMat transportation could be made appropriately and reasonably. The combination of recent interest in expanding or building new facilities to receive liquefied natural gas (LNG) carriers, along with increased awareness and concern about potential terrorist action, has raised questions about the potential consequences of incidents involving LNG transportation. One of those consequences, rapid phase transition (RPT), is studied in this dissertation. The incidents and experiments of LNG-water RPT and theoretical analysis about RPT mechanism are reviewed. Some other consequences, like pool spread and vapor cloud dispersion, are analyzed by Federal Energy Regulatory Commission (FERC) model.
19

Investigation of the distribution and risk factors associated with Mycobacterium avium subspecies paratuberculosis in cow-calf herds in Canada

Douma, Dale Peter 14 April 2011
This thesis summarizes an investigation of Mycobacterium avium subspecies paratuberculosis (Map) as a pathogen within the cow-calf industry in Canada. The specific objectives of this project were to describe the distribution of this pathogen in this industry provincially, as well as at the individual farm level in wildlife species, and in the environment. Secondary objectives of this project were to identify on-farm management risk factors that are associated with this disease and to examine potential options for herd level diagnostic capabilities. Nationally, 0.8% (95%CI = 0.4-1.1%) of the cows in the cow-calf industry were seropositive for Map with 11.7% (95%CI=7.0-16.5%) of the herds sampled having a minimum of one positive test result or 4.5% (95%CI=1.4-7.5%) of the herds having a minimum of two positive test results. The true cow prevalence was estimated as 1.8% (95%CI= 0.4 3.1). No Map was detected in any of the non-ruminant wildlife species sampled on cow-calf operations suggesting that these species were not of primary concern when dealing with the management of this disease. In a study not focussed on a cow-calf operation, Map was detected in one cluster of trapped coyote samples in a region with cow-calf production. The prevalence of Map infection in this cluster of coyotes was calculated to be 9.1% (CI: 5.7-12.5). The prevalence of infection in coyotes including all sites, ignoring the effect of clustering, was calculated to be 3.7% (CI: 2.3-5.1). The use of a commercial colostrum replacement on farm (Odds Ratio =3.96; 95% CI = 1.1014.23, p=0.035) and the presence of wild deer interacting with the cattle (Odds Ratio = 14.32; 95% CI = 1.13181.90, p=0.040) were positively associated with being a herd infected with paratuberculosis. The use of rotational grazing practices was protective (Odds Ratio = 0.20; 95% CI = 0.040.93, p=0.039). It was possible to detect environmental contamination with Map on cow-calf farms using bacterial culture and PCR for confirmation. No water samples were positive to Map; however, 6.2% of the non-water environmental samples were positive. The use of an environmental sampling protocol had a herd sensitivity of 29.6%. This finding led to a simulation modelling study to evaluate how various testing methods would compare in the broader population of cow-calf herds. The final mean risk of selecting a herd infected with Map that was not identified as positive via the herd screen test strategy was 12.9%, 9.8%, 9.6%, and 6.1% for no herd screen test, environmental sampling, ELISA serology, and pooled fecal culture strategies, respectively.
20

An assessment of geospatial technologies as used for wildland fire suppression

Iqbāl, Jāvid 04 June 2010
Wildland fire fighting is complex due to climatic variation, risk and uncertainty, and the proximity of human and resource values. Information about fire environments, resource availability and logistics, fire behavior, and values at risk are important issues fire managers must consider in allocating scarce resources. Improved information thus, has value in reducing risk and costs and damages. Geospatial technology, which includes remote sensing tools, geographic positioning systems (GPS), geographic information systems (GIS) and various maps are widely used in wildland fire management. My research evaluates geospatial tools in three different ways: their role in risk reduction, their effect on wildland fire costs and damages, and wildland fire managers perceived costs and benefits.<p> A theoretical model was developed to analyze the role of geospatial tools in reducing the risk. Risk-averse fire managers were found to use more geospatial technologies compared to those who did not incorporate risk in their decision making, resulting in a creation of value for these technologies. A simultaneous equation system of fires was estimated using the two-stage and the three-stage least squares estimation methods to examine the impact of geospatial tools on fire size, cost and damages. The effect of geospatial technology on fire size was significant in the Full Response Zone. Fire size was positively related to drought and duff moisture codes. Damages and cost of suppression were not affected significantly by the use of digitized maps. The survey of wildland fire managers revealed that geospatial tools are useful in integrating information and provide more clarity, flexibility and accuracy in decision-making. It was also discovered in the survey that geospatial tools are most commonly used when multiple fires are burning at the same time and threatening high resource values. Overall, the findings from this research indicated that risk-averse fire managers use geospatial tools more intensively; that maps play a significant role in reducing the fire size in the Full Response Zone, and, finally, the fire managers view that these technologies are more economically efficient in the Full Response Zone makes a case for more investment in developing and employing them on fires. Record keeping and data collection as well as understanding the human element in terms of risk aversion will be important for future studies and for adopting new technology and allocating resources efficiently.

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